There is a continually increasing demand for radar sensors, wireless telecommunications systems, and the like that call for high frequency integrated circuit (IC) modules. Such modules include, for example, millimeter wave devices, microwave devices, radio frequency wave devices, and the like. The packaging of such modules has a significant effect on their function, their reliability, and the size of end-user devices into which the high frequency IC modules are integrated. For example, the packaging of a high frequency IC module should protect individual devices within the module from interfering with one another, protect transmission lines from interfering with one another and with surrounding devices, and reject electromagnetic interference from external sources. In addition, the packaging should protect the IC module from environmental factors and allow coupling external to the IC module as needed.
IC packaging has evolved through multiple types of packaging technologies. One such packaging technology is known as chips-first packaging. In chips-first packaging, the IC device or devices are at least partially encapsulated in a molding compound. The IC device or devices are then mounted to an inert substrate with their active surfaces face up. Interconnect circuitry can then be built above the active surface of the IC dies. The interconnect circuitry may be formed to the IC device as an integral part of the processing, thus eliminating the need for wire bonds, tape-automated bonds (TABs), solder bumps, or traditional substrate (leadframe or package substrate). Accordingly this packaging technique can support high density interconnect routing, more functionality, and can improve power efficiency, while concurrently facilitating miniaturization, increasing yield, and decreasing cost.
The packaging of high frequency IC modules has been problematic because the individual devices in such an IC module may not be adequately protected from electrical interference and the high frequency transmission lines may not be adequately shielded. These problems are exacerbated with packaging technologies that provide high density interconnect routing and are intended to miniaturize devices, such as chips-first packaging. Accordingly, what is needed is a high-frequency IC module and a method for effectively packaging high-frequency IC devices to form the high-frequency IC module. Such a module and methodology should address signal integrity and electromagnetic interference needs. Furthermore, the methodology should mitigate problems with manufacturing precision and repeatability, while concurrently increasing yields, minimizing size, and minimizing manufacturing costs.